Refactor and Improved Error Handling

crates/bevy_asset/src/lib.rs

@@ -173,14 +173,18 @@ impl Plugin for AssetPlugin {
 
         #[cfg(not(target_arch = "wasm32"))]
         {
-            let temp_source =
-                temp::get_temp_source(app.world_mut(), self.temporary_file_path.clone());
+            match temp::get_temp_source(app.world_mut(), self.temporary_file_path.clone()) {
+                Ok(source) => {
+                    let mut sources = app
+                        .world_mut()
+                        .get_resource_or_insert_with::<AssetSourceBuilders>(Default::default);
 
-            let mut sources = app
-                .world_mut()
-                .get_resource_or_insert_with::<AssetSourceBuilders>(Default::default);
-
-            sources.insert("temp", temp_source);
+                    sources.insert("temp", source);
+                }
+                Err(error) => {
+                    error!("Could not setup temp:// AssetSource due to an IO Error: {error}");
+                }
+            };
         }
 
         {

crates/bevy_asset/src/temp.rs

@@ -1,22 +1,23 @@
-use std::path::{Path, PathBuf};
+use std::{
+    io::{Error, ErrorKind},
+    path::{Path, PathBuf},
+};
 
 use bevy_ecs::{system::Resource, world::World};
 
 use crate::io::AssetSourceBuilder;
 
+/// Private resource to store the temporary directory used by `temp://`.
+/// Kept private as it should only be removed on application exit.
 #[derive(Resource)]
-struct TempAssetDirectory {
-    folder: TempDirectory,
-}
-
-impl TempAssetDirectory {
-    fn path(&self) -> &Path {
-        self.folder.path()
-    }
-}
-
 enum TempDirectory {
+    /// Uses [`TempDir`](tempfile::TempDir)'s drop behaviour to delete the directory.
+    /// Note that this is not _guaranteed_ to succeed, so it is possible to leak files from this
+    /// option until the underlying OS cleans temporary directories. For secure files, consider using
+    /// [`tempfile`](tempfile::tempfile) directly.
     Delete(tempfile::TempDir),
+    /// Will not delete the temporary directory on exit, leaving cleanup the responsibility of
+    /// the user or their system.
     Persist(PathBuf),
 }
 
@@ -32,17 +33,24 @@ impl TempDirectory {
 pub(crate) fn get_temp_source(
     world: &mut World,
     temporary_file_path: Option<String>,
-) -> AssetSourceBuilder {
-    let temp_dir = world.get_resource_or_insert_with::<TempAssetDirectory>(|| {
-        let folder = match temporary_file_path {
+) -> std::io::Result<AssetSourceBuilder> {
+    let temp_dir = match world.remove_resource::<TempDirectory>() {
+        Some(resource) => resource,
+        None => match temporary_file_path {
             Some(path) => TempDirectory::Persist(path.into()),
-            None => TempDirectory::Delete(tempfile::tempdir().expect("todo")),
-        };
+            None => TempDirectory::Delete(tempfile::tempdir()?),
+        },
+    };
+
+    let path = temp_dir
+        .path()
+        .as_os_str()
+        .try_into()
+        .map_err(|error| Error::new(ErrorKind::InvalidData, error))?;
 
-        TempAssetDirectory { folder }
-    });
+    let source = AssetSourceBuilder::platform_default(path, None);
 
-    let path = temp_dir.path().to_str().expect("todo");
+    world.insert_resource(temp_dir);
 
-    AssetSourceBuilder::platform_default(path, None)
+    Ok(source)
 }